The leonine Frenchman Gael Monfils darted this way and that Monday night, showing mesmerized Houston fans why he's considered one of tennis' most relentless retrievers, and made his debut a success.

The only problem was he did so at the expense of one of the most popular players to ply his trade on the red clay at River Oaks Country Club. Over the years James Blake has rarely come up short in any battle decided by athleticism.

Youth is served

But the nearly seven years that separate the 33-year-old American and the 26-year-old Paris-born, Geneva-based pro revealed themselves on more than one occasion as Monfils escaped with a 7-6 (5), 7-5 victory to kick off the U.S. Men's Clay Court Championship in rousing fashion.

Monfils is trying to regain career momentum following a frustrating battle with a severe right knee strain that cost him 3½ months last season and dropped his ranking below 100 after he had been as high as No. 7.

But he showed no sign of the injury in the one hour, 47 minutes he needed to dispatch Blake, the Clay Courts runner-up in 2008.

"Today I was really happy with the way I was moving," Monfils said. "I can truly say the nightmare is now behind me. I am 100 percent (physically)."

Although he wasn't nearly as satisfied with the proficiency of his play, he couldn't quibble with his serve. He hammered 15 aces, becoming just the sixth player with as many in this tournament going back to 1991.

Blake struggled with getting his first serves in, faulting on 53 percent. Only a wicked-kick second serve enabled him to pressure his foe, who repeatedly got his racket on potential winners.

"In my mind, without a doubt, he's the fastest guy out here," Blake said. "If he'd started at a young age, he could have been a world-class sprinter. He's been pretty darned successful at a very high level. He makes (a match) tough because you can't put balls away. You've got to sometimes do it two, three, four times in a point. That's why he's been top 10 and in the semifinals at the French Open. He makes it so hard to close out a point. Combining that with a really big first serve makes it difficult.

"He served well at the end of both sets, and I served really poorly throughout the match. That was the difference."

Resilient Blake

But Blake battled, saving six break points against his serve in the eighth game of the first set while fighting off six others in the match, including one that prevented Monfils from sealing the deal in the second set. He had also jumped out to a 2-0 lead in the set. Only at the finish did Blake succumb without much of a protest, but he didn't have much choice. Monfils served a love game with a pair of aces wide to Blake's backhand, the second of which registered 131 mph on the radar gun.

Despite Blake's fans in Houston, Monfils expressed appreciation for their enthusiasm, slapping his racket for them while they clapped.

"I'd heard it was a great tournament," he said. "The crowd was very fair. It was great. I was happy. And James is a person I like and respect a lot. It's hard for him right now, but I think he's incredible. I'm sure he'll be back."